A flying car flew, a storied aircraft went diesel, and manufacturers in Austria and Brazil celebrated first flights of new airplanes: A number of milestones distinguished 2012 for general aviation as manufacturers strove to bring new products to market.

A production prototype of the Terrafugia Transition flying car, a combination street-legal car and airplane, flew the traffic pattern at Plattsburg, N.Y., on March 23, the company announced on April 2. It marked the first time a Terrafugia prototype has flown around the traffic pattern.

From Massachusetts to the Mojave Desert, and around the world, corporations and backyard builders are fine-tuning designs, hopeful of being the first to deliver a useful aircraft, in numbers, to home garages built for cars.

Since the dawn of aviation, the idea of a "roadable" aircraft, or flying car, has captivated the imagination — intriguing futurists, inspiring dreamers, and spawning a multitude of whimsical and fictional creations — from Chitty Chitty Bang Bang to Blade Runner to The Jetsons. Beyond science fiction, the challenge of producing a real "dual use" vehicle has been more elusive, frustrating inventors and entrepreneurs over the years.

Monster Garage star flies a sports car The Discovery Channel's Monster Garage television show is all about making ridiculously powerful one-of-a-kind machines in ridiculously short periods of time. In five days' time the show's star, Jesse James, and crew converted a donated $90,000 Panoz Esperante sports car built at the Panoz Automobile Company near Atlanta into a flying car and launched it on a 5-foot-high hop on February 25 at the Currituck County Airport not far from Kill Devil Hills, North Carolina.